No, Media General is not headquartered in Montgomery, or even in Alabama, nor do they operate stations in all of the Alabama markets. They bought NBC 13 several years ago after operating CBS 42 for years before. I know Media General also operates WRBL in Columbus, GA and WKRG in Mobile and several daily and weekly papers including the Dothan Eagle.
Raycom Media is headquartered in Montgomery and operates WSFA Montgomery, WBRC Birmingham, WAFF Huntsville, WTVM Columbus, GA, and WDFX Dothan. It does not technically operate a station in the Mobile / Pensacola market, but does operate WLOX Biloxi, an ABC affiliate which most of the cable homes in west Mobile especially receive.